No Water on Two Exoplanets
good news from spitzer space telescope: for the first time, astronomers have been able to analyze chemical signatures in the atmospheres of planets outside of our solar system. the image above demonstrates the basic idea behind how the planetary spectra were obtained: the spectrum of the star (obtained when the planet was passing behind the star) was subtracted from the combined spectrum of the planet and star (obtained when the planet was transiting the star). the most surprising result of the analysis? neither of the two exoplanets that were observed - both gas giants and with such inspiring names as HD 189733b and HD 209458b - showed evidence of water in their atmospheres, though most theories of planetary formation predict the contrary. one of the planets was found to have a very dusty atmosphere full of silicates, suggesting that water may simply be hidden from view (in fact, there are plenty of other reasons why water, even if present, would not show up in the planets' spectra). either way, these observations represent a critical step ahead in our search for life outside of the solar system. here is the nytimes article, and here is the spitzer press release. (image credit: spitzer)
Labels: astrobiology, exoplanets, infrared spectroscopy, spitzer space telescope
posted by Zosia A. C. Krusberg at
8:58 PM
4 Comments:
It reminds me of finding the area between two functions' curves--take the integral under one, subtract out the integral under the other one!
only it's not a nice noise-free analytic function. It's a noisy spectrum from which you're subtracting a second noisy spectrum and then trying to detect lines using models with more uncertainties.
I'm so glad that I don't do spectroscopy.
for real. i think the main point is that though the preliminary results from this study are questionable, they represent an important first step toward future studies of exoplanetary atmospheres and the search for life beyond our solar system. remember: the first confirmed detections of exoplanets really only happened in the 1990's - we've come a long way already!
I think my astro prof from back in the day once mentioned something about a radar telescope using satellites spread really far apart in the solar system going online sometime in our lifetimes, something meant to look more closely at extrasolar planets, but in the years since then, I think I remember hearing about that project losing funding. I can't remember the name of it or find it on google. Anyone here know?
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